Cloned from launchpad blueprint https://blueprints.launchpad.net/python-keystoneclient/+spec/cookie-for-token. Description: Use a secure session cookie (partof the HTTP spec) to store a Key for the the PKIZ tokens after initial use to reduce the size of the HTTP request and response to endpoints. Specification URL (additional information): https://review.openstack.org/#/c/109295/